Chemoenzymatic approaches to the dynamic kinetic asymmetric synthesis of aromatic amino acids

Enzymatic approaches for the production of amino acids by nitrilases are described. Dynamic kinetic asymmetric synthesis conditions were established for the aromatic aminonitriles, phenylglycinonitrile and 4-fluorophenylglycinonitrile, at high pH to produce the corresponding amino acid products in high enantiomeric excess. N-Acylation of aromatic aminonitriles led to spontaneous racemization at pH8, allowing preferential enzymatic hydrolysis of the (R)-enantiomer to afford the product N-acylamino acids in up to 99% enantiomeric excess (ee).